Precast concrete housing

ABSTRACT

A pair of precast concrete building units are joined together to form a modular concrete house. Each concrete building unit includes a floor slab, upright load-bearing exterior walls joined with the perimeter of the floor slab, and a sloping roof cast integrally with the tops of the exterior walls. The building units are arranged so that the roof of each unit slopes upwardly toward the other unit, with the elevated ends of the roofs meeting to form an inverted V-shaped pitch roof. Interior walls are cast integrally with the exterior walls and the roof to divide the building units into separate rooms. The bottoms of the interior walls are spaced above the floor slab so that no loads are transmitted to the floor slab by the walls, and plumbing and wiring are run through the space between the bottom of the interior walls and the floor slab. A reinforcing cage formed from welded wire mesh is embedded in each exterior wall.

United States Patent Cox et al. Aug. 12, 1975 [54] PRECAST CONCRETEHOUSING FOREIGN PATENTS 0R APPLICATIONS 1 lnvemofsl Elmer Adria" COX;Wayne Douglas 768.344 10/1967 Canada 52/79 Riwhey l W s, Jr-. a l 66.36910/1956 France 52/79 of San Antonio, Tex. [73] Assignee; H. B. ZacharyCo., San Antonio, Puma), Exammerpflfred Tex. Attorney, Agent, orF1rmChr1st1e. Parker & Hale [22} Filed: July 2, 1973 57 A CT [21] A l NQ375,844 A pair of precast concrete building units are joined together toform a modular concrete house. Each con- Related Apphcauon Data cretebuilding unit includes a floor slab, upright load- [62] Dllsion of191505 Oct l97|- bearing exterior walls joined with the perimeter of thefloor slab, and a sloping roof cast integrally with the tops of theexterior walls. The building units are ar- [52] j 52/79; 52/9]; 52/221ranged so that the roof of each unit slopes upwardly [51] '3 E04B 7/02;502D 27/42 toward the other unit with the elevated ends of the [58] heldof Search 52/73 22L roofs meeting to form an inverted V-shaped pitch52/234 239 roof. Interior walls are cast integrally with the exteriorwalls and the roof to divide the building units into sep- [56]References C'ted arate rooms. The bottoms of the interior walls areUNITED STATES PATENTS spaced above the floor slab so that no loads aretrans- 2 91 291 10/1954 Henderson 52/79 X mitted to the floor slab bythe walls, and plumbing and 2 769 2l 1 11/1956 Hewitt 1. 52/79 X wiringare run through the space between the bottom 320L907 8/!965 Henderson...52/79 X of the interior walls and the floor slab. A reinforcing 3281453School 1 e A S2/23g cage formed from welded wire mesh is embedded in3,289,368 l2/l966 Mark 52/239 X each eXteriDr wall, 3,557 499 l/l97lDickie et al 52/64 X 3.577.672 5/1971 Nutting 46/24 16 Claims, 22Drawing Figures PATEN [ED H18 1 2 i975 SHEET PATENTED Au: 1 2 I975 SHEETPATENTED AUGI 2 I975 SHEET PATENTEB AUG 1 21975 SHEET w. o O...

PATENTEU AUG 1 2197s SHEET SHEET PATENTED Ant: 1 2191s SHEET KQQWA NW1PRECAST CONCRETE HOUSING This is a division of application Ser. No.191,505, filed Oct. 21, 1971, now U.S. Pat. No. 3,772,835.

BACKGROUND OF THE INVENTION This invention relates to housing, and moreparticularly to precast concrete modular dwelling units.

The recent housing shortage and increase in construction costs hasstimulated the development of prefabricated modular housing. There is aneed especially among low-income families for a durable high qualityhouse that can be mass produced at a lower cost than conventionallybuilt houses.

Most modular housing is in the form of wood frame houses made fromprefabricated building wall panels, frames, and trusses. A majordisadvantage of this type of housing is that the wall panels, frames,and trusses must be constructed with extreme precision on relativelyexpensive framing machines. The prefabricated wall panels, frames, andtrusses then are transported to the building site where substantialadditional costs are incurred in erecting them into houses.

Concrete modular houses also have been produced to satisfy the need forprefabricated housing. Generally, modular concrete houses are assembledfrom concrete modular units, or segments, and separate interior andexterior wall panels. The modular units and wall panels are transportedto the building site where a substantial amount of construction must bedone to erect them into a completed house.

SUMMARY OF THE INVENTION This invention provides a precast concretebuilding unit which may be joined with one or more similar precastconcrete building units to form a concrete modular house. The buildingunits may be precast in a casting yard and transpaorted to theconstruction site where they are placed on a foundation and connectedtogether to form a completed concrete dwelling house.

In its preferred form, each building unit includes a floor slab,exterior walls joined with the floor slab, a roof cast with the exteriorwalls, and interior walls cast with the roof and the insides of theexterior walls. Finishing procedures such as installation of doors,windows, electrical lines, plumbing, and painting are performed at thecasting site. Thus, a minimum amount of construction at the buildingsite is required to connect the buildings together. This work consistsprimarily of setting the modules on the foundation, connecting themtogether, and making the necessary utility connections.

In a preferred form of the modular building unit, the roof, the exteriorwalls, and the interior walls are cast integrally with an appropriatepitch on the roof so that when two of the modular units are joinedtogether, the completed house has a pitch roof. The interior wallspreferably are cast to be spaced above the upper surface of the floorslab when the exterior walls are joined with the floor slab. Thus, noload is transmitted to the floor slab by the interior walls. Anelongated strip of molding on each side of each interior wall covers thespace between the floor slab and the bottom of the interior wall to forman enclosed area for electrical cables, plumbing lines, and the like.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a perspective view showing aprecast concrete modular building unit;

FIG. 2 is a fragmentary plan elevation view showing the floor slabs of apair of side-by-side modular building units which are connected togetherto form a house;

FIG. 3 is an elevation view showing the end of a pair of modularbuilding units connected together to form a house, and an elevation viewof the floor slabs of the building units taken on line 33 of FIG. 2;

FIG. 4 is an enlarged fragmentary elevation view of the reinforcingmeans shown within the circle 4 of FIG.

FIG. 5 is a fragmentary elevation view taken on line 5-5 of FIG. 2showing the reinforcing means for the transverse beams of the floorslab;

FIG. 6 is a plan elevation view showing the floor plan of a completedhouse;

FIG. 7 is a sectional elevation view taken on line 77 of FIG. 6 showingan interior wall of the modular building unit with an electrical outletand an electrical conduit cast in place in the wall;

FIG. 8 is a sectional elevation view taken on line 8-8 of FIG. 6 showingan interior wall of the modular building unit with a gas line betweenthe bottom of the wall and the floor slab;

FIG. 9 is a sectional elevation view taken on line 99 of FIG. 6 showingthe means for reinforcing an exterior wall of the modular building unit;

FIG. 10 is a sectional elevation view showing an alternate form of thereinforcing means shown in FIG. 9;

FIG. 11 is a sectional elevation view showing a further alternate formof the reinforcing means shown in FIG. 9; FIG. I2 is an enlargedelevation view of the means for connecting the roofs shown within thecircle 12 of FIG. 3;

FIG. 13 is a fragmentary schematic elevation view showing means forsecuring an exterior wall to the floor slab;

FIG. 14 is a fragmentary schematic elevation view showing means forsecuring a shear panel between two modular building units;

FIG. 15 is an enlarged fragmentary elevation view taken on line 1515 ofFIG. 14;

FIG. 16 is an elevation view taken on lien 16-16 of FIG. 14;

FIG. 17 is a sectional elevation view showing means for casting theinsulation in the roof of the modular unit;

FIG. 18 is an elevation view showing a reinforcing arch cast in theconcrete surrounding an opening in an exterior wall of the modular unit;

FIG. 19 is a sectional elevation view taken on line l919 of FIG. I8;

FIG. 20 is a fragmentary elevation view showing two alternate modularbuilding units secured together without a shear panel;

FIG. 2! is a plan elevation view taken on line 2I-2l of FIG. 20; and

FIG. 22 is an enlarged elevation view of the means for connecting theroofs shown within the circle 22 of FIG. 20.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. I, aprecast concrete building unit includes a pair of parallel uprightexterior side walls 12, a long exterior end wall 14 (shown in FIG. 3)cast integrally at its ends with a respective end of each side wall, along exterior center wall 16 cast integrally at its ends with the otherends of exterior side walls 12, and a roof 18 which is cast integrallywith the tops of exterior walls, 12, 14, and 16. The roof slopesupwardly toward center wall 16, thereby making the height of center wall16 greater than that of end wall 14.

The exterior walls of building unit 10 are joined with the perimeter ofa rectangular precast concrete floor slab 19 to form a modular concretehalf-dwelling unit 20 which forms half of a completed house 22 shownbest in plan view in FIGS. 2 and 6, and in end view in FIG. 3. The meansfor joining building unit 10 with floor slab 19 will be described indetail below.

Window openings, such as an opening 24 in side wall 12, may be cast ineither of side walls 16 or in end wall 14. One or more doorway openings,such as openings 26, 28, and which are cast in center wall 16, may becast in end wall 14 and either of the side walls, as well as the centerwall. Openings 28 and 30, which are spaced relatively close to eachother, are separated by an interior wall 32 which divides modular unit20 into separate rooms. A second interior wall 34 adjacent door opening26 also divides the unit into separate rooms. Thus, each room indwelling unit 20 has direct access to the mating other half of house 22either through door openings 26, 28, or 30.

Building unit 10 and floor slab 19 are cast separately in a castingyard. Horizontal lifting holes 35 are cast in the long sides of floorslab 19 to receive lifting pins (not shown). A spreader bar (not shown)strapped to the lifting pins hoists the floor slab.

The elevated end portion of roof 18 above center wall 16 is cast in anoutwardly and upwardly projecting overhang 36. A downwardly andoutwardly projecting overhang 38 is cast with the lower edge of roof 18above end wall 14. Longitudinally spaced apart vertical lifting holes 40are cast in each overhang 36 and 38 to permit the passage of liftingdevices, such as cables (not shown), from a gantry crane (not shown)positioned over building unit 10. A lifting arm (not shown) secured tothe end of each cable bears against the undersurface of each overhangportion of the roof to permit the building unit 10 to be lifted when thecables are drawn upwardly by the gantry crane.

Overhang 38 has a flat, horizontal undersurface 42 to permit the wall ofthe casting form (not shown) to be moved horizontally outwardly from endwall 14 without having its movement interrupted by the overhang portionof the roof.

Floor slab 19 is cast as a unit by constructing a rigid reinforcingsteel cage in a mold (not shown) and pouring concrete into the mold toform the floor slab and the beams which project downwardly from theundersurface of the floor slab. The configuration of the preferredreinforcing steel cage is shown best in FIGS. 4 and 5. The horizontalportion of floor slab 19 is reinforced by a horizontal wire mesh panel54 (shown schematically in FIGS 4 and 5) made of pieces of six-gaugewire which are welded together to form a reinforcing grid. The wire meshpanel covers substantially the entire horizontal area of the floor slab.

Spaced apart downwardly opening notches 102 are cast in the bottomsurfaces of the outer transverse beams 46 and large transverse beams 50and 52,

thereby forming spaced apart downwardly projecting teeth or shear keys104 in each beam. When floor slab 19 is placed on a foundation 106(shown best in FIG. 5), the shear keys are embedded in the foundationgrout to form an undulating interface between the floor slab beams andthe foundation, which aids in preventing movement of the housing floorslab 19 relative to the foundation. The shear keys also prevent movementof the floor slab relative to a floor slab of an adjacent modularhalf-dwelling unit 20 which makes up the other half of the completedhouse 22. Foundation 106 preferebly comprises a separate elongatedtrench 107 (see FIG. 4) of pumped-in grout which forms a concrete padbelow each longitudianl beam 44, and separate transverse trenches 108 ofpumpedin grout forming concrete foundation pads below each outertransverse beam 46 and below each of the large transverse beams 50 and52. Before the floor slab is placed on the foundation, levelling pads110 (shown in dotted lines in FIG. 4) are placed at spaced apartlocations in trenches 107. Longitudinal beams 44 rest on the pads whenthe floor slab is placed on the foundation, with a sufficient number ofthe pads being used at each location to level the floor slab.

As shown best in FIG. 5, a separate pair of parallel elongatedreinforcing bars 109, which extend the width of the floor slab, areembedded in foundation grout 106 below each outer transverse beam 46 andbelow each of the large transverse beams 50 and 52. Reinforcing bars 109preferably are number six steel rods. A separate vertically extendinganchor 111 (shown in FIG. 3) embedded in each outer transverse beam 46extends into the foundation grout between the respective pair ofreinforcing bars 109 below it. Each anchor 111 is rigidly secured, suchas by tying or welding, to each of the reinforcing bars 109 to provideadditional resistance to the floor slab 19 and foundation 106 from beingpulled apart. A separate identical anchor 111 embedded in each of thelarge transverse beams 50 and 52 extends into the foundation groutbetween the pair of reinforcing bars 109 below it. Each of these anchorsis rigidly secured by suitable means to a corresponding one of thereinforcing bars 50, 52.

As shown best in FIG. 3, the completed modular house 22 is formed byplacing two modular halfdwelling units 20 parallel to each other onfoundation 106, with the cantilevered overhang 36 of one half closelyspaced from that of the other half so the two roofs 18 cooperate to forma conventional pitch roof. When house 22 is in its assembled form, anelongated open-ended corridor 1 12 is formed between the parallel centerwalls 16. Each half-dwelling unit 20 is placed on its respective floorslab so that the bottom of center wall 16 rests on the horizontal ridge68 of the floor slab. The bottom of each end wall 14 rests on anelongated outwardly projecting horizontal outer ridge 114 castintegrally with the edge on the long side of the floor slab l9 oppositeridge 68. The bottom of each side wall 12 rests on an elongatedoutwardly projecting horizontal ridge 116 (see FIG. 5) cast integrallywith the edge on each short side of the floor slab.

FIG. 4 shows an example of one means for securing the bottom portions ofexterior walls 14 and 16 to the floor slab. The bottom portion of endwall 14 is set in a layer of bonding material 1 17, such as grout, onouter ridge 114 of the floor slab. The bottom of center wall 116 is setin an identical layer of bonding material 117 on bearing surface 68 ofridge 64. The space between the inner edge of each wall and the floorslab is filled with a layer of epoxy grout 118 to complete bonding ofthe walls to the floor slab. FIG. 5 shows an identical means forsecuring the bottom portion of each side wall 12 to the floor slab.

FIG. 13. shows means which are presently preferred for securing thebottom portions of the exterior walls of the floor slab In the exampleshown in FIG. 13, elongated, spaced apart, horizontal anchors bars 120,preferably number six steel rods, are placed between the inside ofexterior side wall 12 and the vertical outer edge of floor slab 19. Theanchor bars preferably are spaced 32 inches apart along the floor slab.An angular L-shaped weld plate 122, which runs the length of the floorslab, is exposed at the vertical edge of the floor slab adjacent toanchor bars 120. The angular weld plate 121 is held in place by spacedapart anchor rods 122 which are embedded in the floor slab. Spaced apartfiat weld plates 123 are exposed along the inside of exterior side wall12 adjacent to each anchor bar 120. Weld plates 123 are held in place byrespective inwardly extending anchor rods 124 which are embedded inexterior side wall 12. It is preferred to place an anchor bar 120 and acoperating weld plate 123 at least 8 inches from the corners of thefloor slab and the corners of any interior walls. One side of eachanchor bar 120 is welded to weld plate 121, and the other side of eachanchor bar is welded to a respective weld plate 123 to rigidly fastenexterior end wall 12 to the floor slab. Access for welding is obtainedby blocking out spaced part notches 125 in the edge of the floor slabadjacent to each anchor bar 120. After welding is completed the blockedout notches are filled with grout 126.

On the other side of the floor slab identical means are used to securecenter wall 16 to the floor slab. Spaced apart anchor bars 127 areplaced between the inside of center wall 16 and the floor slab, with acontinuous angled weld plate 128 embedded in the floor slab on one sideof the anchor bars, and respective spaced apart flat weld plates 129embedded in center wall 16 on the other side of each anchor bar.

Grout 130 is poured in the respective spaces between exterior walls 12and 16 and the floor slab after welding is finished to complete thebonding of the walls to the floor slab.

Means similar to that shown in FIG. 13 preferably are used to secureexterior side walls 14 to the floor slab.

FIG. 12 shows the preferred means for securing together the adjacentends of overhang portions 36 of roofs 18. A separate elongatedright-angle weld plate 131 is exposed at the lower comer of eachoverhang 36, so the two weld plates face each other. Each weld plate 131extends the length of the roof and is held in place by spaced apartelongated anchor rods 132 which are rigidly secured to the inside oftheir respective weld plates and embedded in concrete overhang 36.Anchor rods 132 preferably are spaced 18 inches apart along the lengthof the roof.

An elongated anchor bar 134, which runs the length of the roof, restsbetween weld plates 131. Each weld plate 131 is welded to a respectiveside of anchor bar 134 to rigidly secure the overhang portions of theroofs together. Grout 136 is poured in the space between the ends ofoverhang portions 36 above anchor bar 134 to complete bonding of theroofs.

Referring to FIG. 4, an elongated concrete corridor floor slab 151extends substantially the entire length of the house to provide thefloor for the corridor or hallway 112 between the two halfdwellingunits. The horizontal upper surface of corridor floor slab 151 is in thesame plane as the upper surface of each floor slab 19. A pair ofparallel, laterallly spaced apart. elongated marginal ridges 152 projectdownwardly from the underside of the corridor floor slab along the outeredges of the slab. Each marginal ridge runs the length of the corridorfloor slab, with a separate elongated reinforcing bar 153 being embeddedsubstantially in the center of each ridge. Each reinforcing bar 153 runsthe length of the corridor floor slab and preferably is a number foursteel rod. The corridor floor slab is mounted between the modularhalf-dwelling units so each marginal ridge 152 rests on the outwardlyprojecting horizontal upper surface 68 of a respective one of the ridges64 which extend the length of the corridor.

Preferably, each marginal ridge 152 is set iun grout bed 117 which alsosecures center wall 16 to the floor slab. Spaced apart leveling pads(not shown) may be set below marginal ridges 152 to shim the corridorfloor slab. Grout 117 also fills a portion of the space between theouter edge of the corridor floor slab and the adjacent outer edge of thecenter wall 16. A portion of the space above grout 117 is filled with anepoxy grout 154 to complete bonding of the corridor floor slab to thecenter wall. Alternatively the corridor floor slab may be welded to eachcenter wall in a manner akin to that shown for the exterior walls inFIG. 13.

As shown best in FIGS. 14 through 16 the halfdwelling units are rigidlyinterconnected by a separate upright shear panel 158 at each end ofcorridor 112. Each shear panel 158 preferably is a precast concrete slabwhich is shaped to fit into the opening at each end of the corridor infront of corridor floor slab 151. Each edge of the shear panel is joinedwith the edge of an adjacent center wall 16 by welding it at a pluralityof vertically spaced apart points shown schematically at 159 in FIG. 14,

The preferred means for joining the shear panel to the center wall isshown in FIG. 15 in which vertically spaced apart flat weld plates 160are mounted at the edge of each exterior center wall 16. Each weld plate160 preferably is held in place by a pair of vertically spaced apartanchor rods 162 embedded in center wall 16. The vertical spacing betweenadjacent weld plates 160 preferably is 32 inches. A separate continuousvertical weld plate 164 is mounted at each vertical edge of shear panel158. Each angular weld plate is held in place by spaced apart anchorrods 166 embedded in the shear panel. Spaced apart, vertical elongatedanchor bars 170 are placed between each weld plate 160 and angular weldplate 162. The weld plates are welded to opposite sides of anchor bars170 to rigidly secure each edge of shear panel 158 to a respectivecenter wall 16. Access for welding is obtained by blocked out notches171 formed in each edge of the shear panel adjacent to anchor bars 170.After welding is completed the notches are filled with grout 172.

The lower edges of each shear panel 158 are secured to the outer edgesof beams 44 of the floor slab at points shown schematically at 173 inFIG. 14. Connecting means identical to that shown at 159 in FIG. 15preferably are used to connect the lower portions of the shear panels tothe floor slab beams. The lower edge of each shear panel 158 is embeddedin foundation grout 106 as shown best in FIG. 16. Connecting meansidentical to that shown in FIG. also are preferably used to secure theupper edge of each shear panel to overhang portions 36 of roofs 18.(These connecting means are shown schematically at 174 in FIG. 14).Thus, each shear panel is rigidly secured around its perimeter to centerwalls 16, the longitudinal beams 44 of the floor slab, the foundation106, and the roof overhang 36 to provide the equivalent of at least an 8foot beam which provides substantial rigidity and strength for each endof the completed house. After the shear panels are mounted in place, thespace 176 between the edge of each shear panel and the adjacent centerwalls 16 and roof overhang 36 is filled with grout to complete thebonding of the shear panel to the modular half-dwelling units.

As shown best in FIG. 6, when a short modular halfdwelling unit isinterconnected with a long modular half-dwelling unit, the edge of oneshear panel 158 is secured to the floor slab of the long modular unit inthe same plane as large transverse beam 50 of floor slab l9, and theedge of the other shear panel is secured to the floor slab in the sameplane as large transverse beam 52. This arrangement provides theequivalent of a continuous reinforcing beam running the entire width ofthe completed house at each end of the house.

As shown best in FIG. 6, the exterior side walls 12 and exterior endwalls 14 of each half-dwelling unit have a central core of insulationwhich makes these walls thicker than exterior center walls 16.Preferably, insulated side walls 12 and end walls 14 are about 5 inchesthick, and the center walls are about 3 inches thick. Center walls 16are reinforced by a vertically disposed welded wire mesh panel (notshown) similar to that used to reinforce floor slab 19. FIG. 9 shows adetailed view of the insulation and reinforcing for side wall 12, whichincludes a reinforcing cage formed from laterally spaced apart weldedwire mesh panels 184 which are inserted in the form (not shown) used tocast the side wall. Each welded wire mesh panel 184 is formed fromlongitudinally spaced apart vertically extending wire reinforcing rods186 welded to intersecting vertically spaced apart horisontal wirereinforcing rods 187 (shown schematically in FIG. 9) to form areinforcing grid.

Several concrete interior walls 206 are cast integrally with theinterior of each modular half-dwelling unit. Preferably, the top of eachinterior wall is cast integrally with the underside of roof 18, with atleast one side of the interior wall being cast integrally with theinside of one of the exterior walls. For example, in long modularhalf-dwelling unit 140 shown in FIG. 6, an interior wall 206a extendsapproximately half the width of the modular unit. The end of wall 2060is cast integrally with end wall 14 and at its top is cast integrallywith roof 18. A short interior wall 206b in the same plane as interiorWall 2060 is integral with center wall 16 at its end and with roof 18 atits top. A third interior wall 206c extends the entire width of themodular unit. The ends of wall 2066 are cast integrally with end wall 14and center wall 16, and the top of wall 206( is cast integrally withroof 18. In short modular half-dwelling unit 138, an interior wall 206dextends about threefourths of the width of the unit. One end of wall206d is integral with end wall 14, and the top of wall 206d is integralwith roof 18.

As shown best in FIG. 3, each interior wall 206 is cast so each wall hasa lower surface 208 which is spaced a short distance above the uppersurface of floor slab 19 when the modular half-dwelling units are joinedwith the floor slab. Thus, the interior walls and roof transmit no loadto the thin portion of the floor slab under the interior walls. Instead,the interior walls are held in tension by the roof and at least oneexterior wall, with all the load of the roof and the interior wallsbeing transmitted down through the exterior walls and shear panels.

Preferably, the interior walls 206 are cast so that their bottom edges208 are at least one ionch above the upper surface of floor slab 19. Asshown best in FIG. 7, this spacing permits electrical wiring such as aconventional Romex electrical cable 210 to be run under interior wall206 and connected with a conduit 211 from a conduit box 212 providingelectrical outlets 214. Electrical conduits and conduit boxes are castin place in the interior walls and extension walls. The conduits areprewired prior to casting to facilitate installation of the electricalwiring. Electrica. cables (not shown) strung from a main power source,not shown) are connected to the pre-wired conduits through openings 215(see FIG. 1) which are cast in center wall l6. Preferably, a spacing of1 inch is provided between the bottom 208 of interior wall 206 and floorslab 19 in the arrangement shown in FIG. 7.

FIG. 8 shows another use for the spacing between the bottom of aninterior wall and the floor slab. A larger spacing, preferably 2 or 3inches, is provided for plumbing, such as a water line or gas line 210to be run uonder the interior wall.

The space below each interior wall is enclosed by a separate elongatedstrip of molding 216 extending vertically from each side of the interiorwall to the floor slab. The molding is releasably secured to the walland floor slab to permit access to the electrical lines or plumbing.

The plumbing and wiring are tuun to the exterior of the house throughopenings (not shown) formed in either the floors or walls by blocks (notshown) when the modular dwelling units are cast. The blocks areremovable from the modular units aand the openings are covered bysuitable means after the plumbing or wiring are run through them.

The modular half-dwelling units 20 are particularly suitable for beingproduced and outfitted in completed form in an assembly-line fashion ina casting yard. Floor slab 19 and the walls of building unit 10 are castseparately, with building unit 10 being lifted onto the floor slab atthe casting yard after the concrete has set and the mold forms areremoved. The exterior walls of the building unit are joined with theperimeter of the floor slab to form the outer shell of the modularhalfdwelling unit 20. Shear panels 58 and corridor floor slab 51 arecast as separate units in the casting yard.

The interior of the modular half-dwelling unit also is finished at thecasting site. Plumbing and electrical wiring is run under interior walls206 of each modular unit, and molding strips 216 are fastened to thebottom of each interior wall to finish the interior walls. Insulationpanels 200 are mounted against center walls 16 if the completed house isto include a long unit and short unit. A ceiling (not shown) made ofnonload-bearing wallboards such as gypsum wallboard is placed onmounting tracks (not shown) in the upper portion of each modularhalf-dwelling unit. A similar ceiling is mounted in the upper portion ofcorridor 112 to form an attic space. Several removable nonload-bearingvertical wall panels 242 (see FIG. 6) are placed on mounting tracks (notshown) on the floor slab and ceiling to separate the interior of themodular unit into rooms and to provide partitioning for closets and thelike. Door jambs (not shown) are constructed, exterior doors 244 andinterior doors (not shown) are mounted, windows 246 are installed, andthe exterior and interior of the modular unit are painted. Interiorfixtures such as a bathtub and kitchen facilities also are preferablyadded at the casting site.

The completed modular half-dwelling units are then transported to thebuilding site where they are assembled to form a completed house. Twounits are set sideby-side on foundation 106. The overhang portions 36 ofthe roofs 18 are connected together, and the corridor floor slab 151 ismounted between half-dwelling units. Shear panels 158 are then mountedat the ends of the house to connect the half-dwelling units to gether.An air conditioning and heating unit 248 (see FIG. 6) is mounted in theupper portion of the corridor at one end of the house. Ducts 250 in theattic space above the ceiling in the corridor deliver air from theheating and air conditioning unit to each room in the house. The ductsopen into each room through openings 252 (see FIG. 1) which are cast incenter walls 16. Exterior trimming (not shown) is then added to thehouse and the house is in its completed form ready for use as a singlefamily dwelling unit.

I claim:

I. A precast concrete building unit comprising a floor slab, severalprecast concrete structural panels above the floor slab, said structuralpanels comprising at least two load-bearing exterior walls joined withthe floor slab, a roof cast integrally with the exterior walls, and aninterior wall having an end which is cast integrally with at least oneof the exterior walls and a top which is cast integrally with the roof,the interior wall having an undersurface spaced from the upper surfaceof the floor slab so that the interior wall does not transmit a load tothe floor slab.

2. Apparatus according to claim 1 in which the roof of the building unitis sloped so that the elevated portion of the roof may be joined withthe elevated portion of the roof on a substantially identical buildingunit to form a modular house with an inverted V-shaped pitch roof.

3. Apparatus according to claim 1 including an elongated strip ofmolding on each side of the interior wall for covering the space betweenthe floor slab and the bottom of the interior wall to fonn an enclosedarea for electrical cables, plumbing lines, and the like.

4. A precast concrete building unit for mounting on a floor slab, thebuilding unit comprising at least two upright load-bearing exteriorwalls, each exterior wall having a respective bottom edge, means forjoining the exterior walls to the floor slab, and an interior wall castintegrally with at least one of the exterior walls, the interior wallhaving a bottom edge which is spaced above the bottom edge of eachexterior wall a sufficient dis tance such that the interior wall doesnot transmit a load to the floor slab when the exterior walls are joinedwith the floor slab.

5. Apparatus according to claim 4 including a roof cast integrally withthe tops of the exterior walls, and

in which the interior wall has a top which is cast integrally with theroof.

6. Apparatus according to claim 5 in which the roof of the building unitslopes upwardly toward one end of the building unit, and including asecond identical building unit having a roof which slopes upwardlytoward one end, the two building units being arranged so the elevatedends of the roofs are adjacent each other, and means for joiningtogether the elevated ends of the two roofs so the two building unitsform a modular dwelling unit with an inverted V-shaped pitch roof.

7. Apparatus according to claim 6 in which one of said exterior walls ofeach building unit is cast integrally with the elevated end of the roofof its respective building unit, and in which the elevated end of eachsloping roof is formed as a cantilevered overhang above its respectiveexterior wall so the two building units form an elongated corridorbetween the two exterior walls when the elevated ends of the roofs arejoined together.

8. A precast concrete building unit comprising a floor slab, at leastone structural panel above the floor slab, an interior wall castintegrally with the structural panel, the undersurface of the interiorwall being spaced from the upper surface of the floor slab so that theinterior wall does not transmit a load to the floor slab, and anelongated strip of molding on each side of the interior wall forcovering the space between the floor slab and the bottom of the interiorwall to form an enclosed area for electrical cables, plumbing lines, andthe like.

9. Apparatus according to claim 8 including several precast concretestructural panels above the floor slab, said structural panelscomprising at least two loadbearing exterior walls joined with the floorslab, and a roof cast integrally with the exterior walls, the interiorwall having an end which is cast integrally with at least one of theexterior walls and a top which is cast integrally with the roof.

10. A precast concrete building unit comprising a floor structure havinga top surface, at least one upright cast concrete load-bearing exteriorwall joined with the floor structure and extending above the top surfaceof the floor structure, a roof cast integrally with at least one of theexterior walls, and an interior wall having an end which is castintegrally with at least one of the exterior walls and a top which iscast integrally with the roof, the interior wall being supported abovethe top surface of the floor structure by the exterior wall and roofwith which it is cast, the interior wall extending for a major portionof the height of the exterior wall with which it is cast and having anundersurface spaced above the top surface of the floor structure so thatthe interior wall does not transmit a load to the floor structure and sothat the space between the undersurface of the interior wall and the topsurface of the floor structure provides room for electrical cables.plumbing lines, and the like.

11. Apparatus according to claim 10 in which the floor structure is aprecast concrete floor slab, and including means joining the bottoms ofthe exterior walls to the floor slab.

12. Apparatus according to claim 10 including a plumbing line for thebuilding unit disposed in the space between the interior wall and thefloor structure.

13. A precast concrete bilding unit comprising a floor slab having a topsurface, at least one upright cast concrete load-bearing exterior walljoined with the floor slab and extending above the top surface of thefloor slab. a roof cast integrally with the exterior walls, and aninterior wall cast integrally with at least one of the exterior wallsand with the roof so the interior wall extends over the floor slab, theinterior wall having an undersurface which is spaced above the topsurface of the floor slab so the interior wall does not transmit a loadto the floor slab and so that the space between the undersurface of theinterior wall and the top surface of the floor slab provides room forelectrical cables. plumbing lines, and the like.

14. Apparatus according to claim 13 including an elongated strip ofmolding on each side of the interior wall for covering the space betweenthe floor slab and the bottom of the interior wall to form an enclosedarea for said electrical cables, plumbing lines, and the like.

15. A precast concrete building unit comprising a floor structure havinga top surface. at least one upright cast concrete load-bearing exteriorwall joined with the floor structure and extending above the top surfaceof the floor structure, and an interior wall cast integrally with atleast one of the exterior walls and supported above the top surface ofthe floor structure by the exterior wall with which it is cast. theinterior wall extending for a major portion of the height of theexterior wall with which it is cast and having an undersurface spacedabove the top surface of the floor structure so that the interior walldoes not transmit a load to the floor structure and so that the spacebetween the undersurface of the interior wall and the top surface of thefloor structure provides room for electrical cables, plumbing lines, andthe like. and an elongated strip of molding on each side of the interiorwall for covering the space between the floor structure and theundersurface of the interior wall to form an enclosed area for saidelectrical cables. plumbing lines, and the like.

[6. Apparatus according to claim 15 including a plumbing line for thebuilding unit disposed in the enclosed area between the interior walland the floor structure.

* :r as =1:

UNITED STATES PATENT AND TRADEMARK OFFWE 'ZERTIFH'IATE 0F CORREQEEQNPATEN'l NO. 1 3,898,776

IM'ENTGWS! 1 Elmer A. Cox et a].

H is cerifved that sum appears in the amve-identifiec patert Md thatsaid Letters Pale-mt an: Merely corrected Shawn below.

[75] Inventors: "Adrian" should read Adrain Q01. 1, line 39,transpaorted" should read transported Col 2, line 35.. "FIG. 3; FIG. 12should read FIG, 9;

FIG. 12 (a new paragraph);

line 46, "lien" should read line -u 30].' 4, line 14, "lon-gitudianl"should read longitudinal Col. .3, line 10, "anchors" should read "anchorline 25, "coperating should read cooperating Col. 6, line 4,halfdwelling" should read half-dwelling line 26, "iun" should read inline 41, should read Col. 8, line 13, "ionoh" should read inch line 33,"uonder" should read under line 4v, "tnun" should read run line 44,"aand" should read and Zol. lO line 66, "bilding" should read building{Claim 13;

Signed and Bealzd this fourth D 3} or November 1975 {SEAL} Arrest:

RUTH C. MASON C. MARSHALL DANN Arm-1mg Officer Commissioner n/Palems andTrademark:

1. A precast concrete building unit comprising a floor slab, severalprecast concrete structural panels above the floor slab, said structuralpanels comprising at least two load-bearing exterior walls joined withthe floor slab, a roof cast integrally with the exterior walls, and aninterior wall having an end which is cast integrally with at least oneof the exterior walls and a top which is cast integrally with the roof,the interior wall having an undersurface spaced from the upper surfaceof the floor slab so that the interior wall does not transmit a load tothe floor slab.
 2. Apparatus according to claim 1 in which the roof ofthe building unit is sloped so that the elevated portion of the roof maybe joined with the elevated portion of the roof on a substantiallyidentical building unit to form a modular house with an invertedV-shaped pitch roof.
 3. Apparatus according to claim 1 including anelongated strip of molding on each side of the interior wall forcovering the space between the floor slab and the bottom of the interiorwall to form an enclosed area for electrical cables, plumbing lines, andthe like.
 4. A precast concrete building uNit for mounting on a floorslab, the building unit comprising at least two upright load-bearingexterior walls, each exterior wall having a respective bottom edge,means for joining the exterior walls to the floor slab, and an interiorwall cast integrally with at least one of the exterior walls, theinterior wall having a bottom edge which is spaced above the bottom edgeof each exterior wall a sufficient distance such that the interior walldoes not transmit a load to the floor slab when the exterior walls arejoined with the floor slab.
 5. Apparatus according to claim 4 includinga roof cast integrally with the tops of the exterior walls, and in whichthe interior wall has a top which is cast integrally with the roof. 6.Apparatus according to claim 5 in which the roof of the building unitslopes upwardly toward one end of the building unit, and including asecond identical building unit having a roof which slopes upwardlytoward one end, the two building units being arranged so the elevatedends of the roofs are adjacent each other, and means for joiningtogether the elevated ends of the two roofs so the two building unitsform a modular dwelling unit with an inverted V-shaped pitch roof. 7.Apparatus according to claim 6 in which one of said exterior walls ofeach building unit is cast integrally with the elevated end of the roofof its respective building unit, and in which the elevated end of eachsloping roof is formed as a cantilevered overhang above its respectiveexterior wall so the two building units form an elongated corridorbetween the two exterior walls when the elevated ends of the roofs arejoined together.
 8. A precast concrete building unit comprising a floorslab, at least one structural panel above the floor slab, an interiorwall cast integrally with the structural panel, the undersurface of theinterior wall being spaced from the upper surface of the floor slab sothat the interior wall does not transmit a load to the floor slab, andan elongated strip of molding on each side of the interior wall forcovering the space between the floor slab and the bottom of the interiorwall to form an enclosed area for electrical cables, plumbing lines, andthe like.
 9. Apparatus according to claim 8 including several precastconcrete structural panels above the floor slab, said structural panelscomprising at least two load-bearing exterior walls joined with thefloor slab, and a roof cast integrally with the exterior walls, theinterior wall having an end which is cast integrally with at least oneof the exterior walls and a top which is cast integrally with the roof.10. A precast concrete building unit comprising a floor structure havinga top surface, at least one upright cast concrete load-bearing exteriorwall joined with the floor structure and extending above the top surfaceof the floor structure, a roof cast integrally with at least one of theexterior walls, and an interior wall having an end which is castintegrally with at least one of the exterior walls and a top which iscast integrally with the roof, the interior wall being supported abovethe top surface of the floor structure by the exterior wall and roofwith which it is cast, the interior wall extending for a major portionof the height of the exterior wall with which it is cast and having anundersurface spaced above the top surface of the floor structure so thatthe interior wall does not transmit a load to the floor structure and sothat the space between the undersurface of the interior wall and the topsurface of the floor structure provides room for electrical cables,plumbing lines, and the like.
 11. Apparatus according to claim 10 inwhich the floor structure is a precast concrete floor slab, andincluding means joining the bottoms of the exterior walls to the floorslab.
 12. Apparatus according to claim 10 including a plumbing line forthe building unit disposed in the space between the interior wall andthe floor structure.
 13. A precast concrete Bilding unit comprising afloor slab having a top surface, at least one upright cast concreteload-bearing exterior wall joined with the floor slab and extendingabove the top surface of the floor slab, a roof cast integrally with theexterior walls, and an interior wall cast integrally with at least oneof the exterior walls and with the roof so the interior wall extendsover the floor slab, the interior wall having an undersurface which isspaced above the top surface of the floor slab so the interior wall doesnot transmit a load to the floor slab and so that the space between theundersurface of the interior wall and the top surface of the floor slabprovides room for electrical cables, plumbing lines, and the like. 14.Apparatus according to claim 13 including an elongated strip of moldingon each side of the interior wall for covering the space between thefloor slab and the bottom of the interior wall to form an enclosed areafor said electrical cables, plumbing lines, and the like.
 15. A precastconcrete building unit comprising a floor structure having a topsurface, at least one upright cast concrete load-bearing exterior walljoined with the floor structure and extending above the top surface ofthe floor structure, and an interior wall cast integrally with at leastone of the exterior walls and supported above the top surface of thefloor structure by the exterior wall with which it is cast, the interiorwall extending for a major portion of the height of the exterior wallwith which it is cast and having an undersurface spaced above the topsurface of the floor structure so that the interior wall does nottransmit a load to the floor structure and so that the space between theundersurface of the interior wall and the top surface of the floorstructure provides room for electrical cables, plumbing lines, and thelike, and an elongated strip of molding on each side of the interiorwall for covering the space between the floor structure and theundersurface of the interior wall to form an enclosed area for saidelectrical cables, plumbing lines, and the like.
 16. Apparatus accordingto claim 15 including a plumbing line for the building unit disposed inthe enclosed area between the interior wall and the floor structure.